Multi-SIM devices, such as cellular telephones, are devices that include more than one subscriber identification module (SIM). Multi-SIM devices have become increasing popular because of the versatility that they provide, particularly in countries where there are many service providers. For example, dual-SIM devices may allow a user to implement two different cellular service subscriptions or plans with different service providers, with separate numbers and bills, on the same device (e.g., business account and personal account). In addition, during travel, users can obtain local SIM cards and pay local call rates in the destination country. By using multiple SIMs, a user may take advantage of different service pricing plans and save on mobile data usage.
Multi-SIM multi-active (MSMA) devices have two or more SIMs using at least two separate radio resource chains. For example, a dual-SIM dual-active (DSDA) device can separately accommodate simultaneous wireless services. However, when both wireless services are voice calls, only one of those simultaneous voice calls may be active at a time because DSDA devices use one speaker and one microphone for conducting a voice call. Thus, the DSDA device places one voice call (i.e., the non-active voice call) in a hold state while the other voice call (i.e., the active call) uses the speaker and microphone. Other than merging the two calls into a conference call (which may be undesirable in most circumstances), a user has no way of talking/listening on two active voice calls at the same time.